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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Old 20th Nov 2019, 18:16
  #4041 (permalink)  
 
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Originally Posted by Takwis View Post
It would have been rather handy, if Boeing had mentioned that after the Lion Air crash. They were adamant that the pilots weren't trimming enough, though. Much commentary was made, here, about those little comments after AUTOPILOT-DISENGAGE, about getting the aircraft back in trim BEFORE cutting off the stab trim switches.

See "Evolution of Stab Trim Runaway Procedure", 737 Runaway Stabilizer Procedure
Or had the AD stated that suspected MCAS runaway could be held at bay by momentary blips (up or down) of the trim switches at < 5 second intervals but warned to expect it to re-engage 5 seconds after last input..
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Old 20th Nov 2019, 18:26
  #4042 (permalink)  
 
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Originally Posted by MurphyWasRight View Post
Or had the AD stated that suspected MCAS runaway could be held at bay by momentary blips (up or down) of the trim switches at < 5 second intervals but warned to expect it to re-engage 5 seconds after last input..
Or ANYTHING to let the pilots know it was there, and how it worked.
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Old 20th Nov 2019, 19:55
  #4043 (permalink)  
 
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Originally Posted by MurphyWasRight View Post
Or had the AD stated that suspected MCAS runaway could be held at bay by momentary blips (up or down) of the trim switches at < 5 second intervals but warned to expect it to re-engage 5 seconds after last input..
The FCOM Bulletin No. TBC-19, dated November 6, 2018 (the day before the AD), includes the following:

The Multi Operator Message sent by Boeing on November 10, 2018 included the following:

The FCOM Bulletin and the Multi Operator Message are included in the Lion Air reports.

I haven't seen an explanation of why this detail was not included in the AD.
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Old 20th Nov 2019, 22:45
  #4044 (permalink)  
 
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Relevant insofar as the FAA's credibility has taken a dent, it is perhaps worth re-posting a link to one of the interviews with DP Davies, the former ARB/CAA certification test pilot.

The fourth and final podcast covers Concorde and the British V-bombers. But listen on to about the 35 minute mark for his frank views on the FAA - even in 1992 he was shall we say decidedly skeptical...

I can't post a URL I'm afraid, but a quick search (the interviews are on aerosociety - dot - com) will find them.
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Old 20th Nov 2019, 23:00
  #4045 (permalink)  
 
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Originally Posted by skwdenyer View Post
Relevant insofar as the FAA's credibility has taken a dent, it is perhaps worth re-posting a link to one of the interviews with DP Davies, the former ARB/CAA certification test pilot.

The fourth and final podcast covers Concorde and the British V-bombers. But listen on to about the 35 minute mark for his frank views on the FAA - even in 1992 he was shall we say decidedly skeptical...

I can't post a URL I'm afraid, but a quick search (the interviews are on aerosociety - dot - com) will find them.
There is a sticky post at top of tech log that points to those as well. (Have not followed it but from name looks to be same).
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Old 20th Nov 2019, 23:43
  #4046 (permalink)  
 
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Salute!

From Tak....
Or ANYTHING to let the pilots know it was there, and how it worked.
Gotta tellya that I would hunt down whoever implemented an undocumented/advertised flight control modification to the plane I flew for 20 years or so, and enjoyed. The meeting would not be pleasant. My Special Ops background comes into play - "You can run, but you'll only die tired!"

Regardless of how MCAS was supposed to work, the thing needed to be advertised to we lowly pilots just in case that the one in a zillion chance it would acvtivate without being at "x" AoA, and well short of an actual stall AoA ( although MCAS is not an "anti-stall" feature, huh?) My God. Beam Me Up!!!

Gums sends...
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Old 21st Nov 2019, 00:43
  #4047 (permalink)  
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Originally Posted by gums View Post
. . . although MCAS is not an "anti-stall" feature, huh? . . .
Yeah. Have you noticed that hardly anyone has shown up to argue that it's all about stick force for some time, now?

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Old 21st Nov 2019, 05:34
  #4048 (permalink)  
 
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Old 21st Nov 2019, 08:35
  #4049 (permalink)  
 
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There was an interesting programme on Chan 4 (UK TV) last night on this topic. Much was made of the 2 accidents but the interesting bits involved two 737 pilots, one American and one British, in a simulator and they were caught out by the action of MCAS. After the instructions re operating the trim cut out switches were added to the relevant instructions, they still failed to "save" the aircraft. The reason seems to have been due to their having operating the cut out switches too late. It was suggested that, for the cut out switches to be effective, they have to be operated within 4 seconds of the onset of the upset and they took a little longer. By the time they threw the switches, the aircraft was diving toward the ground so fast that manual efforts to recover by heaving on the yoke came to nothing. The aerodynamic force being exerted on the stabilizer was such that they were unable to overcome it.
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Old 21st Nov 2019, 08:41
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Originally Posted by KelvinD View Post
There was an interesting programme on Chan 4 (UK TV) last night on this topic.
No sign of it online on Channel 4 "Catch Up" but is is to be repeated as follows - it seems. 1h ish program.

21 Nov 10pm 4Seven
Sunday 9pm 4Seven
Wed 27 nov 11:05pm Ch 4
Tue 3 Dec 2:20am 4seven
Tue 3 Dec 11:05pm 4seven
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Old 21st Nov 2019, 09:36
  #4051 (permalink)  
 
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the interesting bits involved two 737 pilots, one American and one British, in a simulator and they were caught out by the action of MCAS
Seems unlikely. They were in a NG simulator.
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Old 21st Nov 2019, 09:51
  #4052 (permalink)  
 
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Originally Posted by jimjim1 View Post
No sign of it online on Channel 4 "Catch Up" but is is to be repeated as follows - it seems. 1h ish program.

21 Nov 10pm 4Seven
Sunday 9pm 4Seven
Wed 27 nov 11:05pm Ch 4
Tue 3 Dec 2:20am 4seven
Tue 3 Dec 11:05pm 4seven
Appears to be available online here
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Old 21st Nov 2019, 09:56
  #4053 (permalink)  
 
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I watched C4 last night and there was not much new in it. I was under the impression that one of the problems with the Ethiopian crash was that the pilots left the thrust levers at climb power and did not slow the aircraft down in order to use the manual trim wheel effectively which as speed increased became ever more problematic - the simulator reconstruction did not appear to feature any reduction in thrust. Please feel free to correct me if I am barking up the wrong tree !
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Old 21st Nov 2019, 10:47
  #4054 (permalink)  
 
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In the B737NG simulator...If the pilot flying is applying nose up elevator it is much harder for the pilot monitoring to move the manual stabiliser trim wheel.
If the pilot flying offloads the elevator it is much easier to apply manual trim...not sure if this applies at VNE.
Stab trim cutoff, manual trim (offload elevator if possible), < 250 knots flaps 1 then 5 (nose up pitch)?
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Old 21st Nov 2019, 13:30
  #4055 (permalink)  
 
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(pax). I can't say I found the programme very instructive, been covered in this thread with less emotion. Don't think the significance of excess speed on manual inputs, or using the cut outs when already badly out of trim, were made but I guess it suited the intended audience.
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Old 21st Nov 2019, 18:29
  #4056 (permalink)  
 
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Originally Posted by B744IRE View Post
In the B737NG simulator...If the pilot flying is applying nose up elevator it is much harder for the pilot monitoring to move the manual stabiliser trim wheel.
If the pilot flying offloads the elevator it is much easier to apply manual trim...not sure if this applies at VNE.
Stab trim cutoff, manual trim (offload elevator if possible), < 250 knots flaps 1 then 5 (nose up pitch)?
Heading downhill, at rapid ROD, close to the ground, no pilot is going to release up elevator to try and use manual trim !!!!!
Self preservation cuts in with instinctive action to PULL, just as it was with the Valiant when training for a runaway stab.
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Old 21st Nov 2019, 18:35
  #4057 (permalink)  
 
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Heading downhill, at rapid ROD, close to the ground, no pilot is going to release up elevator to try and use manual trim !!!!!
Yeah. You would think that would be obvious by now....
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Old 21st Nov 2019, 18:45
  #4058 (permalink)  
 
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Originally Posted by Grebe View Post
SideNote -- re the Boeing BS described as " Now, according to the Boeing website, it has over 45,000 engineers spread throughout the entire company. Such a deep roster of talent, the aerospace company has incredibly deep and specific expertise for new designs and to manage the safety and airworthiness of the nearly 14,000 Boeing airplanes flying today."

look up the following in the JDA Journal "FAA Insight and Aviation . . ."

Hi all. I'm the author mentioned here, so: In partial response to the comment about the number of transport category airplanes, go to Page 13 of Boeing's "Statistical Summary of Commercial Jet Airplane Accidents Worldwide Operations | 1959 – 2017". I'm not allowed to post a link yet, haven't been in this forum long enough, but the Boeing report can be found by Googling the title - it presents some really interesting data. Boeing claims to have 13,871 of their products alone in the active fleet - I suspect that's plenty close enough to claim "nearly 14,000". As for the number of Boeing engineers working in Boeing Commercial, that was just a WAG, it was a difficult number to find but I DID find the ~45,000 in the Boeing website.
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Old 21st Nov 2019, 19:40
  #4059 (permalink)  
 
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Boeing Corp seem to have lost their way of late.
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Old 21st Nov 2019, 20:58
  #4060 (permalink)  
 
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Boeing has a plane in the air as I post this on Thursday at 4PM EST... still working through what appears to be slow speeds in turns, but this is a 737-700 from the looks of it:

https://flightaware.com/live/flight/...845Z/KBFI/KBFI
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